Doyne Lecture. Pathogenesis of retinal pigment epithelial detachment in the elderly; the relevance of Bruch's membrane change

Boundary-Repairing Dual-Path Network for Retinal Layer Segmentation in OCT Image with Pigment Epithelial Detachment

Automatic retinal layer segmentation in optical coherence tomography (OCT) images is crucial for the diagnosis of ocular diseases. Currently, automatic retinal layer segmentation works well with normal OCT images. However, pigment epithelial detachment (PED) dramatically alters the retinal structure, causing blurred boundaries and partial disappearance of the Bruch's Membrane (BM), thus posing challenges to the segmentation. To tackle these problems, we propose a novel dual-path U-shaped network for simultaneous layer segmentation and boundary regression. This network first designs a feature interaction fusion (FIF) module to strengthen the boundary shape constraints in the layer path. To address the challenge posed by partial BM disappearance and boundary-blurring, we propose a layer boundary repair (LBR) module. This module aims to use contrastive loss to enhance the confidence of blurred boundary regions and refine the segmentation of layer boundaries through the re-prediction head. In addition, we introduce a novel bilateral threshold distance map (BTDM) designed for the boundary path. The BTDM serves to emphasize information within boundary regions. This map, combined with the updated probability map, culminates in topology-guaranteed segmentation results achieved through a topology correction (TC) module. We investigated the proposed network on two severely deformed datasets (i.e., OCTA-500 and Aier-PED) and one slightly deformed dataset (i.e., DUKE). The proposed method achieves an average Dice score of 94.26% on the OCTA-500 dataset, which was 1.5% higher than BAU-Net and outperformed other methods. In the DUKE and Aier-PED datasets, the proposed method achieved average Dice scores of 91.65% and 95.75%, respectively.

SPATIAL PATTERN OF RETINAL PIGMENT EPITHELIUM TEAR DEVELOPMENT AND PROGRESSION AFTER ANTIVASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY FOR NEOVASCULAR AGE-RELATED MACULAR DEGENERATION

PURPOSE

The aim of this study was to demonstrate the spatial pattern of retinal pigment epithelium (RPE) tear development and progression after antivascular endothelial growth factor therapy for neovascular age-related macular degeneration.

METHODS

We retrospectively reviewed six eyes with neovascular age-related macular degeneration that showed RPE tears after administration of intravitreal antivascular endothelial growth factor agents and were followed up for 12 months. The patterns of RPE tear development and progression were evaluated by analyzing positional relationships among the locations of the choroidal neovascularization membrane and pigment epithelial detachment (PED) area at baseline and the tear area using spectral-domain optical coherence tomography, color photography, fluorescein angiography, and fundus autofluorescence images.

RESULTS

Pretear OCT images revealed fibrovascular PED in all eyes, one of which showed complications of hemorrhagic PED after treatment. In five eyes, RPE tears developed at the PED edge located on the opposite side of the choroidal neovascularization membrane. In the eye showing hemorrhagic PED, the RPE tear developed along the wide area of the PED edge. The torn RPE monolayer contracted toward the side of the choroidal neovascularization membrane in all eyes, and RPE loss involved the fovea in five eyes that showed significantly worse visual acuity (VA) after 12 months in comparison with the baseline value before the tear (logMAR VA; 0.3 vs. 1.29; P < 0.02).

CONCLUSION

The location of choroidal neovascularization membrane in PED determines the spatial pattern of RPE tear development and progression and helps to predict the visual outcome after RPE tears.

Spontaneous Massive Retinal Pigment Epithelium Tear: A Case Report of a Dramatic Complication of Age-Related Macular Degeneration

Retinal pigment epithelium (RPE) tears occur when the RPE acutely breaks and retracts, leaving the underlying Bruch's membrane and choroid exposed. They usually happen in areas of previous pigment epithelial detachments and are generally associated with age-related macular degeneration (AMD). The purpose of this report is to describe a case of a spontaneous massive central RPE tear in a patient with untreated AMD. A 67-year-old female patient presented with complaints of sudden decreased vision in her right eye. Her best-corrected visual acuity was 2/20, and fundoscopy revealed a massive central retinal hemorrhage with intraretinal, subretinal, and sub-RPE blood. The patient started anti-vascular endothelial growth factor (VEGF) treatment, and after the blood was reabsorbed, a very large central tear of the RPE involving the central macula was evident, with a layer of detached retina folded on itself. She received continuous anti-VEGF therapy, and the final measurement of her visual acuity was 2/200, despite the complete reabsorption of the hemorrhage. RPE tears may occur spontaneously as part of the natural history of AMD or be triggered by the initiation of anti-VEGF treatment in the presence of large pigment epithelium detachments. There are currently no strategies to prevent their spontaneous development, and they constitute a dramatic complication of AMD. The prognosis is dependent on the size and location of the lesion, and the visual loss is irreversible.

Bacillary Layer Detachment in Neovascular Age-Related Macular Degeneration: Case Series

PURPOSE

This study seeks to report the clinical and multimodal imaging findings of eight eyes of seven patients with neovascular age-related macular degeneration (nAMD) who developed bacillary layer detachment (BALAD). Setting/Venue: The patients were analysed at the Western Eye Hospital in London, UK.

METHODS

The approaches of this research include clinical examinations and multimodal imaging-based description of cases of nAMD with BALAD.

RESULTS

We report multimodal imaging findings of bacillary layer detachment (BALAD) in patients with nAMD.

CONCLUSIONS

A bacillary layer detachment was detected in patients with neovascular age-related macular degeneration. This multimodal imaging finding is not commonly described in the literature for this disease.

Choroidal structural features of acquired vitelliform lesions in non-exudative age-related macular degeneration

PURPOSE

To define the choroidal morphological characteristics of non-exudative age-related macular degeneration (AMD) cases associated with acquired vitelliform lesions (AVLs).

METHODS

This retrospective study included intermediate AMD patients with AVLs (Group1, 21eyes) and without AVLs (Group2, 21eyes). A healthy control group was (Group3, 23eyes) also included. Subfoveal choroidal thickness (SFCT), greatest basal diameter (GBD), and maximum height (MH) of the largest PED were measured on spectral domain optical coherence tomography. Internal reflectivity of PEDs and total choroidal area (TCA) were measured using ImageJ software. The TCA was binarized to the luminal area (LA) and stromal area. The choroidal vascularity index (CVI) was assessed.

RESULTS

The mean SFCT, TCA, and LA were higher in Group 1 (290.3 ± 86.8 μm, 0.840 ± 0.302 mm², 0.602 ± 0.227 mm²) than in Group 2 (215.6 ± 85.0 μm, 0.594 ± 0.183 mm², 0.429 ± 0.139 mm²) (p = 0.014, p = 0.017, p = 0.020, respectively). There was no significant difference in the CVI measurements between Group 1 and Group 2 (p = 1.000). The mean GBD and MH of the PED was higher in Group 1 (1443 ± 595 µm, 188 ± 86 µm) than in Group 2 (851 ± 368 µm, 119 ± 38 µm) (p = <0.001, p = 0.001, respectively). Internal PED reflectivity was significantly lower in Group 1 (0.44 ± 0.21) than in Group 2 (0.66 ± 0.17) (p = <0.001). Internal PED reflectivity showed negative correlation with GBD and MH of the PED in Group 1 (r = -0.587, p = 0.005; rho = -0.448, p = 0.042, respectively). In Group 2, internal PED reflectivity had a negative correlation with MH of the PED (rho = -0.511, p = 0.018).

CONCLUSION

Non-exudative AMD patients with AVLs are more prone to have a thick choroid and large hyporeflective PEDs as compared to the those without AVLs.

AGE-RELATED RETENTIONAL AVASCULAR PIGMENT EPITHELIAL DETACHMENT VIEWED WITH INDOCYANINE GREEN ANGIOGRAPHY

PURPOSE

Age-related scattered hypofluorescent spots on late-phase indocyanine green angiography (ASHS-LIA) might represent hydrophobic neutral lipid deposits in the Bruch membrane. This study aimed to report retentional avascular pigment epithelial detachment (PED) associated with ASHS-LIA.

METHODS

Patients aged ≥50 years who presented a single avascular serous PED without soft drusen or any other retinal or choroidal diseases were retrospectively included. Pigment epithelial detachment was classified as retentional, effusional, or mixed PED based on indocyanine green angiography. Multimodal images were qualitatively and quantitatively evaluated.

RESULTS

This study included 74 eyes of 57 patients. Retentional PED, effusional PED, and mixed PED accounted for 91.9%, 4.1%, and 4.1%, respectively. All PEDs were located in the macular region. Seventeen (29.8%) included patients had bilateral PEDs and all were retentional PEDs with a high level of bilateral consistency in the characteristics of PED and ASHS-LIA. All retentional PEDs were within the bounds of ASHS-LIA. The area of retentional PED increased with the ASHS-LIA grade ( P = 0.030).

CONCLUSION

Most age-related avascular serous PEDs are retentional PEDs. The location and area of retentional PEDs are consistent with the distribution of ASHS-LIA. These findings suggest that the hydrophobic neutral lipid deposits in the Bruch membrane might be involved in the pathogenesis and be a therapeutic target in age-related retentional avascular PED.

Blue-light fundus autofluorescence imaging of pigment epithelial detachments

BACKGROUND

Pigment epithelial detachments (PEDs) occur in association with various chorioretinal diseases. With respect to the broad clinical spectrum of PEDs we describe fundus autofluorescence (FAF) characteristics of PEDs.

METHODS

Ninety-three eyes of 66 patients (mean age 71.9 ± 11.1) with uni- or bilateral PED ( ≥ 350 µm) were included in a retrospective cross-sectional study. PEDs were secondary to age-related macular degeneration (n = 79), central serous chorioretinopathy (n = 7), polypoidal choroidal vasculopathy (n = 2), pattern dystrophy (n = 3) or idiopathic PED (n = 2). FAF images were recorded using confocal scanning laser ophthalmoscopy (488 nm excitation wavelength, detection of emission >500 nm). Diagnosis of PED was confirmed using spectral-domain optical coherence tomography. A qualitative FAF grading system was established, and grading was performed by two independent readers.

RESULTS

PEDs showed highly variable characteristics on FAF imaging. FAF within the area of PED was found to be irregular/granular (n = 59, 63.4%), increased (n = 28, 30.1%), decreased (n = 3, 3.2 %), or normal (n = 3, 3.2%). Accompanying FAF changes included condensation of macular pigment (n = 67, 72.0%), focally increased FAF at the PED apex (n = 14, 15.1%) or elsewhere (n = 52, 55.9%), focally decreased FAF (n = 23, 24.7%), a cartwheel-like pattern (n = 10, 10.8%), a doughnut sign (n = 6, 6.5%), and a halo of decreased FAF encircling the PED (completely n = 20, 21.5% or incompletely n = 20, 21.5%).

CONCLUSIONS

PEDs show a variety of abnormal patterns on FAF imaging. These changes in FAF signals may be secondary to morphological and metabolic alterations within corresponding retinal layers and do not necessarily correspond with the underlying PED subtype or a specific pathology.

ANATOMIC AND FUNCTIONAL IMPROVEMENT OF A DRUSENOID PIGMENT EPITHELIAL DETACHMENT: A CASE REPORT

BACKGROUND/PURPOSE

Age-related macular degeneration is the most prevalent cause of permanent vision loss in the developed world. Drusenoid pigment epithelial detachments are a biomarker of age-related macular degeneration disease progression and typically result in poor visual prognosis. Low luminance visual acuity (LLVA) has been previously been shown to correlate with the severity of age-related macular degeneration. However, the degree of spontaneous improvement of this functional outcome is still under investigation.

METHODS

Observational clinical case report.

RESULTS

A drusenoid pigment epithelial detachment that increased in size with the development of hyperreflective foci spontaneously improved with restoration of normal foveal contour over the span of 41 months without progression to geographic atrophy or choroidal neovascularization. Although best-corrected visual acuity remained stable both before and after the pigment epithelial detachment resolution, low luminance visual acuity decreased from a baseline of 59 (20/63 -1) to 39 (20/160 -1) letters over 17 months. However, over the subsequent 24 months, low luminance visual acuity improved by 35 letters to 74 letters (20/32 -2).

CONCLUSION

Drusenoid pigment epithelial detachments can resolve without treatment. Low luminance visual acuity seems to correlate with the anatomic improvement and can improve spontaneously by more than six lines of vision.

Age‐related maculopathy in the light of ischaemia

This manuscript focuses on the pathogenesis of age-related maculopathy (ARM) and the documentation of new treatments in ARM. Ischaemia will be given special consideration, as it is believed to play a central role in both early ARM and late ARM or age-related macular degeneration (AMD). Reduced choroidal and retinal blood flow causes ischaemia of Bruch's membrane, retinal pigment epithelium and neuroretina in the early course of ARM. This is thought to be the primary trigger of the condition. Chronic ischaemia upregulates vascular endothelial growth factor (VEGF), which induces abnormal vessel growth in neovascular AMD. The role of ischaemia in neovascular AMD is supported by the evidence of effective new treatments targeting VEGF.

THE OCCURRENCE, CHARACTERISTICS, MANAGEMENT, AND PROGNOSIS OF RETINAL PIGMENT EPITHELIUM TEARS IN PATIENTS WITH POLYPOIDAL CHOROIDAL VASCULOPATHY: A Retrospective Study of 397 Patients

PURPOSE

To investigate retinal pigment epithelium (RPE) tears in patients with polypoidal choroidal vasculopathy.

METHOD

A retrospective review of polypoidal choroidal vasculopathy cases with confirmed RPE tears was conducted. Patients' comprehensive clinical data were collected and analyzed. The treatment strategy was a loading dose of one intravitreal antivascular endothelial growth factor injection, combined with additional injections if exudative activities or visual deterioration were detected.

RESULTS

Among 397 polypoidal choroidal vasculopathy patients, 33 patients with RPE tears (8.3%) were included. 42.4% of them happened spontaneously. Pigment epithelial detachment (PED) occurred more frequently in RPE tear patients and most of them had serous vascularized or hemorrhagic PED. The height and greatest linear diameter of PED, and the subfoveal choroidal thickness of these cases were significantly larger, whereas the central foveal thickness was significantly smaller. Most of the RPE tears occurred at the edge of the PED. After our treatment strategy, patients' best-corrected visual acuity improved significantly from 2.13 ± 1.24 (median 20/52) to 1.32 ± 1.31 (median 20/166). Large subretinal hemorrhage may increase the risk of the formation of subretinal fibrosis (P < 0.05).

CONCLUSION

Retinal pigment epithelium tears in polypoidal choroidal vasculopathy are associated with high subRPE hydrostatic pressure, produced by a large PED or hemorrhage. After our intervention strategy, this condition may not necessarily result in poor prognosis.

Retinal Pigment Epithelial Detachment in Age-Related Macular Degeneration

Retinal pigment epithelial detachment is defined as a separation of the retinal pigment epithelium from the inner collagenous layer of Bruch’s membrane. It is a common manifestation in both dry and wet types of age-related macular degeneration. This review aims to provide a comprehensive guide to the pathophysiology, clinical and imaging characteristics, natural course and treatment of the various types of pigment epithelial detachments in order to assist in diagnosis and management of this important feature of age-related macular degeneration.

Treatment of large avascular retinal pigment epithelium detachments in age-related macular degeneration with aflibercept, photodynamic therapy, and triamcinolone acetonide

Purpose

To evaluate the use of aflibercept, triamcinolone acetonide, and photodynamic therapy (PDT) in the treatment of avascular pigment epithelium detachments (aPEDs).

Patients and methods

Patients with treatment-naïve aPEDs ≥1,500 µm in diameter were randomized to treatment or observation. Treatment consisted of 6 monthly intravitreal injections of aflibercept. If the aPED persisted, the patients were treated with half-fluence PDT in combination with intravitreal triamcinolone acetonide and aflibercept. The primary outcome was change of best-corrected visual acuity (BCVA) after 24 months of follow-up. Secondary outcomes were changes in pigment epithelium volume, height and diameter, central retinal thickness, and number of patients developing choroidal neovascularization or geographic atrophy (GA).

Results

Treatment and inclusion of patients were stopped after an interim analysis of 6-month data because 75% of the aPEDs were in different stages of GA. Nine patients with aPED were included in the study, of these one patient was excluded because of bilateral central serous chorioretinopathy. The remaining eight had drusenoid aPEDs. After 24 months of follow-up, estimated means of BCVA decreased by 4.2 and 20.8 letters in the treatment and observation group, respectively. This decrease over time was not significantly different between groups (P=0.140, 95% CI −5.3, 38.6). Estimated means of PED volume, height, diameter, and central retinal thickness were not significantly different between groups. Choroidal neovascularization and retinal pigment epithelium tear developed in one patient in the treatment group. One patient in the treatment group and two patients in the observation group progressed to complete retinal pigment epithelium and outer retinal atrophy. A decrease in PED volume was associated with the development of complete retinal pigment epithelium and outer retinal atrophy (P=0.029).

Conclusion

This small trial indicates that multitargeted, primarily antiangiogenic therapy does not favorably alter the natural course of drusenoid aPEDs.

Retinal pigment epithelial tears

A retinal pigment epithelial (RPE) tear is a well-known complication of retinal pigment epithelial detachments (PED) and may cause a significant visual impairment. The most common cause is a vascularized PED in patients with exudative age-related macular degeneration (AMD). The development of diagnostic imaging techniques brings us closer to the etiology and pathophysiological mechanisms of this entity, offering us new strategies for treatment and follow-up. The advent of intravitreal antiangiogenic treatment (anti-VEGF) has led to an increase in the number of reported cases of RPE tears, which are an important vision-limiting factor during treatment. However, RPE tears may occur spontaneously or as a consequence of thermal laser treatment, photodynamic therapy or anti-VEGF therapy. It is accepted that the mechanism of RPE tears is multifactorial. The optimization of the functional outcome of this complication has been described with continuous treatment with antiangiogenic drugs. The goal of the present review is to evaluate the incidence, risk factors and treatment of RPE tears.

WRINKLED VASCULARIZED RETINAL PIGMENT EPITHELIUM DETACHMENT PROGNOSIS AFTER INTRAVITREAL ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY

BACKGROUND/PURPOSE

Neovascular age-related macular degeneration (nAMD) is frequently associated with vascularized pigment epithelial detachment (v-PED). We observed a peculiar characteristic of v-PED characterized by small lacy folds of the retinal pigment epithelium, appearing as a wrinkled PED (w-PED) on spectral domain optical coherence tomography (SD-OCT). Our purpose was to describe the visual prognosis and number of intravitreal injections in w-PED compared with non-w-PED.

METHODS

In this retrospective, case-control series, we reviewed retrospectively medical records of 52 eyes of 51 patients who were consecutively included between November 1 and 30, 2015 with a previous minimum 3-year follow-up. Inclusion criteria were: neovascular age-related macular degeneration, affected with w-PED. Baseline characteristics, best-corrected visual acuity (BVCA), number of intravitreal anti-vascular endothelial growth factor injections (anti-VEGF IVT) and maximal recurrence-free interval, that is, without intravitreal anti-vascular endothelial growth factor injection, were analyzed. A w-PED was defined as a v-PED ≥200 μm in height on SD-OCT imaging, presenting with at least 4 small lacy folds on the surface of the retinal pigment epithelium. Patients were compared with a control group, that is, patients harboring PED without wrinkle shape (non-w-PED). All patients had been treated by intravitreal anti-vascular endothelial growth factor injection of either ranibizumab (IVR) or aflibercept (IVA) using a pro re nata (PRN) protocol after three initial monthly treatments, with a minimum of follow-up of 3 years.

RESULTS

Two groups of patients were compared, w-PED (29 eyes, from 29 patients), and non-w-PED (23 eyes from 22 patients). In the w-PED group, mean BCVA evolved from 0.28 (±0.18) log MAR (20/40, range 20/25-20/63) at baseline, to 0.29 (±0.21) log MAR (20/40, range 20/25-20/63) at 1 year (P = 0.41), 0.34 (±0.26) log MAR (20/40, range 20/25-20/80) at 2 years (P = 0.49), 0.35 (±0.28) log MAR (20/40, range 20/25-20/80) at 3 years (P = 0.54). In the non-w-PED group, mean BCVA was 0.40 (±0.28) log MAR (20/50, range 20/25-20/100) at baseline and decreased to 0.48 (±0.46) log MAR (20/63, range 20/20-20/160) at 1 year (P = 0.19), 0.48 (±0.35) log MAR (20/63, range 20/25-20/125) at 2 years (P = 0.02), 0.60 (±0.38) log MAR (20/80, range 20/32-20/200) at 3 years (P = 0.002). In the w-PED group, the mean maximal documented recurrence-free interval was 7.87 (±2.94) months at Year 1, 13.5 (±7.52) at Year 2 and 14.78 (±10.70) at Year 3, versus 4.59 (±2.95) months at Year 1, 7.83 (±6.62) at Year 2, 8.57 (±11.18) at Year 3 in the non-w-PED group (P = 0.0004; 0.0101; 0.0168 respectively at Years 1, 2 and 3).

DISCUSSION

The evolution of v-PED after intravitreal anti-vascular endothelial growth factor injection is still difficult to predict despite intense clinical research in this topic. In our study, we noticed that w-PED might be a phenotypic prognosis factor for better visual acuity and longer maximal recurrence-free interval.

Treatment of Macular Degeneration with Sildenafil: Results of a Two-Year Trial

OBJECTIVE

To evaluate PDE5/6 inhibition with sildenafil to reduce choroidal ischemia and treat age-related macular degeneration.

METHODS

Sildenafil was prescribed to treat participants with macular degenerations or macular dystrophies measured by spectral-domain optical coherence tomography, color fundus photography, enhanced depth imaging, and best-corrected visual acuity.

RESULTS

No change in calcified drusen was noted. Vitelliform-type soft drusen were not substantially changed. A participant with Best vitelliform macular dystrophy had a significant improvement in vision as well as in photoreceptor and ellipsoid layers.

CONCLUSIONS

Our research supports sildenafil as a safe treatment for age-related and vitelliform macular degenerations. Thickened Bruch's membrane reduces the beneficial effect of perfusion increase, but all eyes appear to benefit from PDE6. Notably, maintenance or improvement in the photoreceptor layer may be the most significant result of sildenafil and is consistent with PDE6 inhibition. Thus, sil-denafil treatment of macular degeneration offers significant potential for vision retention and recovery.

Age-Related Macular Degeneration: Review of Pathogenesis

Age-related macular degeneration is a condition (a) characterized by accumulation of membranous debris on both sides of the retinal pigment epithelium (RPE) basement membrane. Clinical manifestations of drusen, atrophy of the RPE/choriocapillaris, RPE detachment, and choroidal new vessel (CNV) formation occur after age 50 years. A hypothetical pathogenic sequence of events consistent with known data is: 1) RPE dysfunction (e.g., precipitated by an inherited susceptibility and/or environmental exposure); 2) accumulation of intracellular material in the RPE (e.g., accumulation of normal substrate material that is not enzymatically degraded properly vs. abnormal substrate material); 3) abnormal accumulation of extracellular material (basal laminar and basal linear deposit); 4) change in Bruch's membrane composition (e.g., increased lipid deposition and protein crosslinking); 5) change in Bruch's membrane parmeability to nutrients (e.g., impaired diffusion of water soluble plasma constituents across Bruch's membrane); and 6) response of the RPE to metabolic distress (i.e., atrophy vs. CNV growth). Histopathological and clinical studies indicate that areas of choroidal ischemia often are seen near CNVs in AMD patients. In response to decreased oxygen delivery/metabolic “distress”, the RPE may elaborate substances leading to CNV growth. Perhaps RPE atrophy, followed by choriocapillaris and photoreceptor atrophy, is a response to decreased nutrients/increasing metabolic abnormalities in areas of excessive accumulation of extracellular debris. Unanswered questions regarding AMD include: 1) is AMD an ocular manifestation of a systemic disease or purely an ocular disease?; 2) what determines whether CNVs vs.atrophy of the RPE-choriocapillaris-photoreceptors develops?; and 3) what induces the maturation of CNVs into an inactive scar, and what limits the growth of most CNVs to the area centralis?

Morphologic Criteria of Lesion Activity in Neovascular Age-Related Macular Degeneration: A Consensus Article

Intravitreal antivascular endothelial growth factor drugs represent the current standard of care for neovascular age-related macular degeneration (nAMD). Individualized treatment regimens aim at obtaining the same visual benefits of monthly injections with a reduced number of injections and follow-up visits, and, consequently, of treatment burden. The target of these strategies is to timely recognize lesion recurrence, even before visual deterioration. Early detection of lesion activity is critical to ensure that clinical outcomes are not compromised by inappropriate delays in treatment, but questions remain on how to effectively monitor the choroidal neovascularization (CNV) activity. To assess the persistence/recurrence of lesion activity in patients undergoing treatment for nAMD, an expert panel developed a decision algorithm based on the morphological features of CNV. After evaluating all current retinal imaging techniques, the panel identified optical coherent tomography as the most reliable tool to ascertain lesion activity when funduscopy is not obvious.

FOCAL CHOROIDAL EXCAVATION AND ITS ASSOCIATION WITH PACHYCHOROID SPECTRUM DISORDERS: A Review of the Literature and Multimodal Imaging Findings

PURPOSE

To review the literature regarding focal choroidal excavation and show its association with pachychoroid features through case examples.

METHODS

The clinical manifestations of focal choroidal excavation are illustrated with various imaging modalities inclusive of fundus photography, fundus autofluorescence, fluorescein angiography, indocyanine green angiography, spectral domain optical coherence tomography (OCT), enhanced depth imaging OCT, and swept-source OCT.

RESULTS

Diffuse or focal areas of choroidal thickening with dilated choroidal vessels (pachyvessels) on OCT and choroidal hyperpermeability on indocyanine green angiography are present in many eyes with focal choroidal excavation. Clinical and imaging features of associated comorbidities including central serous chorioretinopathy and choroidal neovascularization are described.

CONCLUSION

Focal choroidal excavation appears to be a manifestation of pachychoroid spectrum disease associated with choroidal thickening and pachyvessels on structural OCT and choroidal hyperpermeability on indocyanine green angiography.

Retinal Pigment Epithelium Tear

Retinal pigment epithelium tear is a potentially vision threatening complication of retinal pigment epithelial detachment associated with neovascular age-related macular degeneration. Retinal pigment epithelium tear has been reported to occur spontaneously and after treatment with anti-vascular growth endothelial factor agents. The current study summarizes the presentation, diagnosis, management, and outcomes of retinal pigment epithelium tears.

Prospective evaluation of the incidence and risk factors for the development of RPE tears after high- and low-dose ranibizumab therapy

PURPOSE

To prospectively determine the incidence and risk factors for retinal pigment epithelial (RPE) tears in eyes with vascularized pigment epithelial detachments (PED) and exudative age-related macular degeneration receiving antivascular endothelial growth factor therapy.

METHODS

Eyes were prospectively randomized into 1 of 4 arms: 1) 0.5 mg of ranibizumab monthly for 12 months; 2) 0.5 mg of ranibizumab monthly for 3 months and then pro re nata on the basis of clinical and optical coherence tomography-guided indications; 3) high-dose 2.0 mg of ranibizumab monthly for 12 months; or 4) 2.0 mg of ranibizumab monthly for 3 months and then pro re nata thereafter. All PEDs were measured for height, greatest linear diameter, and surface area at baseline. The incidence of RPE tears in the entire 4-arm cohort was determined at the end of 12 months. Eyes were divided into two groups (tear vs. nontear) and statistically compared to determine risk factors for the development of RPE tear.

RESULTS

Of 37 eyes, a total of 5 developed postranibizumab RPE tears during the course of the study (incidence 14%). Four of the 5 tears occurred in the high-dose 2.0-mg groups. Baseline PED height, surface area, and greatest linear diameter were significantly greater in the group that developed RPE tears versus the nontear group (P = 0.018, 0.031, and 0.048, respectively). There were significantly more eyes with PED height >550 microns in the RPE tear group (4 of 5, 80%) compared with the nontear group (9 of 32, 18%) (P = 0.042). The presence of PED height >550 microns was associated with an increased tear rate from 14% to 31%. Furthermore, retrospective identification of a ring sign or Grade 1 tear at baseline, in addition to PED height >550 microns, was associated with a further increase in the tear rate to 67%.

CONCLUSION

In this study, the prospective incidence of RPE tears was ∼14%. A baseline PED height >550 microns and presence of a Grade 1 tear, or positive ring sign, were identified as high-risk factors for the subsequent development of an RPE tear.

Mechanism of retinal pigment epithelium tear formation following intravitreal anti-vascular endothelial growth factor therapy revealed by spectral-domain optical coherence tomography

PURPOSE

To demonstrate the mechanism by which retinal pigment epithelium (RPE) tears occur in eyes with neovascular age-related macular degeneration (AMD) treated with intravitreal anti-vascular endothelial growth factor (VEGF) agents using spectral-domain optical coherence tomography (OCT).

DESIGN

Retrospective observational case series.

METHODS

OCT images of 8 eyes that developed RPE tears following the administration of intravitreal anti-VEGF agents for neovascular AMD were evaluated. Pretear and posttear images were compared in order to elucidate the mechanism by which RPE tears occur in this setting.

RESULTS

In all eyes, pretear images revealed a vascularized pigment epithelial detachment (PED) containing hyperreflective material consistent with choroidal neovascularization (CNV). This CNV was adherent to the undersurface of the RPE and created contractile folds in the RPE contour. In 6 eyes, contractile neovascular tissue spanned the PED, causing outward bowing of the Bruch membrane and a peaked appearance to the overlying RPE monolayer. RPE tears occurred after the first anti-VEGF injection in 6 of 8 eyes. The posttear OCT images showed a discontinuity in the RPE with the CNV adherent to the retracted RPE. In all eyes, the RPE ruptured along a segment of bare RPE not in contact with the CNV or Bruch membrane.

CONCLUSIONS

Eyes with vascularized PEDs secondary to AMD may show specific OCT findings that increase the risk for RPE tear following intravitreal anti-VEGF injection. Rapid involution and contraction of neovascular tissue adherent to the undersurface of the RPE may impart a substantial contractile force that tears this already-strained tissue layer.

Reduced-fluence photodynamic therapy for subfoveal serous pigment epithelial detachment with choroidal vascular hyperpermeability

PURPOSE

To evaluate the efficacy of reduced-fluence photodynamic therapy (PDT) for treating symptomatic subfoveal serous pigment epithelial detachments (PEDs) with hyperfluorescence on late-phase indocyanine green angiography (ICGA) without choroidal neovascularization (CNV).

DESIGN

Retrospective, interventional case series.

METHODS

Fifteen eyes of 15 patients (mean age, 55.3 years) with a serous PED were included. Baseline ICGA showed hyperpermeable choroidal vessels but no CNV in any eyes. Reduced-fluence PDT was applied and included treatment of hyperfluorescent areas on late-phase ICGA. We evaluated changes in the PEDs and hyperfluorescence on late-phase ICGA at baseline and 3 months after PDT. We compared the subfoveal choroidal thickness and best-corrected visual acuity (BCVA).

RESULTS

The baseline ICGA showed mild to intense hyperfluorescence at the PED with hyperpermeable choroidal vessels. One month after reduced-fluence PDT, the PED resolved in 14 eyes (93%) and decreased in height in 1 eye. The PED flattening continued for more than 3 months. The baseline hyperfluorescence on ICGA decreased at month 3 except for 1 eye. The subfoveal choroidal thickness decreased significantly (P < .0001) from 297 to 238 μm; the BCVA significantly (P = .019) improved from 0.08 to -0.01 between baseline and month 3. The month-3 BCVA was significantly associated with the baseline BCVA and the duration and size of the PED. No PEDs recurred or complications developed, such as secondary CNV or retinal pigment epithelial tears.

CONCLUSION

Serous PEDs accompanying hyperfluorescence on ICGA are considered a variant of central serous chorioretinopathy. Reduced-fluence PDT is beneficial for resolving PEDs.

Serous pigment epithelial detachment in age-related macular degeneration: comparison of different treatments

AIMS

To investigate the therapeutic effects of different treatments on serous pigment epithelium detachment (PED) in age-related macular degeneration (AMD).

METHODS

A total of 328 patients suffering from serous PED in AMD were retrospectively analysed. We treated only patients with documented visual deterioration: 86 patients with bevacizumab, 128 with ranibizumab, 60 with pegaptanib, and 54 with photodynamic therapy (PDT) combined with intravitreal triamcinolone acetonide (IVTA). Best-corrected vision was determined in the logarithm of the minimal angle of resolution (logMAR). We also analysed morphological findings such as full foveal thickness by optical coherence tomography (OCT), manually calculated height of PED as measured by OCT, and fluorescence angiography.

RESULTS

The mean follow-up was 42.4 weeks. The best-corrected visual acuity of 0.78 logMAR before treatment could be improved by about 0.066 logMAR after treatment. Retinal thickness decreased in all patients with PED, in the mean by about 64.06 microm, and the mean value of the manually calculated height decreased by about 0.98 units. All functional and morphological results proved to be significantly better after injection of ranibizumab and bevacizumab than after pegaptanib and the combined treatment with PDT and IVTA. In all, 41 (12.5%) of our patients developed a tear of the retinal pigment epithelium (RPE).

CONCLUSION

The therapeutic results were significantly better in patients treated with bevacizumab and ranibizumab than in those treated with pegaptanib or with a combination of PDT and IVTA. Even with treatment, tears of the RPE or only a partial flattening of the PED always indicated a worse prognosis in eyes with exudative AMD than in eyes with classic choroidal neovascularization.

Treatment of retinal pigment epithelial detachment with antiangiogenic therapy

Purpose

Evaluate the efficacy of pegaptanib, a selective anti-vascular endothelial growth factor (VEGF) agent, and bevacizumab, a nonselective anti-VEGF agent, for retinal pigment epithelial detachment (PED) associated with occult choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

Methods

Prospective, comparative, nonrandomized pilot study included patients with PED comprising >50% of total lesion in subfoveal location with visual acuity (VA) 20/40–20/400 and lesions either previously untreated or treated only with photodynamic therapy/verteporfin. Seven patients received pegaptanib 0.3 mg intravitreally (IVT); eight received IVT bevacizumab 1.25 mg. Follow-up occurred every 4–6 weeks for 6 months. Reinjection of initial medication occurred if there was intra- or subretinal fluid observed by optical coherence tomography (OCT) or increased PED. Endpoints were mean changes from baseline to month 6 in VA (ETDRS) and foveal thickness.

Results

At baseline, mean VA was lower, and mean foveal thickness was greater in pegaptanib versus bevacizumab-treated patients (36.1 vs 49.5 letters; 470.4 vs 321.1 μm). Mean improvements to month 6 in VA and foveal thickness were greater for pegaptanib (VA: +9.1 vs +7.2 letters; foveal thickness: −88.2 vs −52.9 μm). On average, pegaptanib-treated patients had slower but more sustained improvement in VA and foveal thickness; bevacizumab-treated patients showed rapid improvement with a slow return towards baseline. Both agents were well tolerated.

Conclusion

Intravitreal injections of pegaptanib or bevacizumab are both efficacious and safe treatments for PED associated with occult CNV secondary to AMD.

Enhanced depth imaging optical coherence tomography of retinal pigment epithelial detachment in age-related macular degeneration

PURPOSE

To describe the internal structure of pigment epithelial detachments (PEDs) seen in eyes with age-related macular degeneration (AMD) as imaged with enhanced depth imaging (EDI) spectral-domain optical coherence tomography (OCT).

DESIGN

Retrospective observational case series.

METHODS

The images were obtained by positioning a spectral-domain OCT device close enough to the eye to obtain an inverted image and 7 sections, each comprised of 100 averaged scans, were obtained within a 5 degrees x 15 degrees or larger rectangle to encompass the PED and accompanying neovascularization if present. The resultant images were reinverted and compared with fluorescein and indocyanine green angiographic findings.

RESULTS

The full extent of the choroid was visualized under the PED in each of the 22 consecutive eyes imaged with EDI OCT. The entire PED cavity filled with hyperreflective tissue in 11 eyes. In the remaining 11 regions, what appeared to be serous fluid and collections of reflective material were found within the PED. The reflective material was seen to be contiguous with subretinal pigment epithelial neovascularization, had angiographic suggestive of fibrovascular proliferation, and was seen to course up along the back surface of the retinal pigment epithelium (RPE). Intravitreal ranibizumab injection caused PED flattening with apparent contracture of the accumulated material within the PED.

CONCLUSIONS

PEDs in the context of AMD show material suggestive of choroidal neovascularization, frequently on the back surface of the RPE. These findings can help explain the pathogenesis of PEDs, retinal vascular anastomosis with choroidal neovascularization, and RPE tears.

Retinal pigment epithelial detachment

Detachment of the retinal pigment epithelium is a prominent feature of many chorio-retinal disease processes, the most prevalent of which is age-related macular degeneration (AMD). Detachment of the retinal pigment epithelium may or may not be associated with choroidal neovascularization and may be caused by different types of pathogenesis, each associated with distinct angiographic features, natural course, visual prognosis, and response to treatment. The phrase "detachment of the retinal pigment epithelium" is used quite often, not always in the correct association and with no clear differentiation between its various types. It is important to identify the specific nature of detachment of the retinal pigment epithelium, and to establish an accurate diagnosis and treatment plan. Therefore, we present a review of the existing types of detachment of the retinal pigment epithelium with what we propose as being appropriate nomenclature and classification, and potential treatment recommendations.

Functional loss in early age-related maculopathy: the ischaemia postreceptoral hypothesis

We review proposed models and psychophysical and electrophysiological tests performed in many studies for early age-related maculopathy (ARM). We suggest that ischaemia is the trigger for impaired retinal pigment epithelium function causing imbalance of secretion of vascular growth factors, reduced disc degradation capability and reduced metabolic activity and possible inflammatory response. This results in increased deposition of cell debris, such as drusen and thickens Bruch's membrane causing even more ischaemia of the overlying neurosensory retina. The photoreceptors are more resistant to ischaemia given their proximity to the choroid. Furthermore, being 'upstream' from the inner retinal layers, they act as an oxygen sink depriving retinal layers further from the choroid. Postreceptoral cell layers and especially parts of the inner nuclear layer that are located in the watershed zone between two sources of blood supply are preferentially vulnerable to ischaemia. Based on psychophysical and electrophysiological findings we propose that most of the function impairment in early ARM starts postreceptorally.

HMG CoA reductase inhibitors (statins): do they have a role in age-related macular degeneration?

Age-related macular degeneration is a progressive late onset disease affecting central vision. It is the leading cause of irreversible blindness in developed countries, and with the aging population the problem is increasing. Current treatment options are limited to the late stage of the disease when central vision is already under great threat, and even new treatments make little impact on the rate of blindness. Intervention earlier in the disease may prove more rewarding, but to date little progress has been made with this approach. Epidemiologic, genetic, and pathological evidence continues to accumulate, suggesting a possible link between risk factors for cardiovascular diseases and age-related macular degeneration. This article reviews the evidence and discusses the rationale behind the recent suggestions that cholesterol-lowering agents may be useful in the treatment of early age-related macular degeneration. The cholesterol-lowering family of drugs called statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) inhibitors with pleiotropic actions. Their therapeutic effects in cardiovascular disease and dyslipidaemia have been well proven. In this review we will outline the known actions of statins and discuss possible ways that they may impact on age-related macular degeneration.

Changes in fundus autofluorescence in patients with age-related maculopathy. Correlation to visual function: a prospective study

BACKGROUND

As members of the Fundus Autofluorescence in Age-related Macular Degeneration Study Group (FAM Study Group), we report changes of fundus autofluorescence (AF) in patients with multiple soft drusen in correlation to visual function.

METHODS

Inclusion criteria were age >50 years, the presence of soft drusen, visual acuity of 20/100 or better, and no previous laser treatment in the study eye. All patients underwent a detailed ophthalmological examination including ETDRS visual acuity, binocular funduscopy, and color fundus photography. AF imaging was performed with a confocal scanning laser ophthalmoscope following a standard protocol. We used the classification of the International Fundus Autofluorescence Classification Group (IFAG) for the description of the AF patterns.

RESULTS

One hundred and twenty-five patients (81 women, 44 men) aged from 55 to 86 years (mean 70+/-7 years) were included in this prospective study. During follow-up (mean 18+/-6 months), 6 of 35 eyes with patchy AF pattern developed exudative changes, as well as 2 eyes with focal-plaque-like AF pattern and 1 eye with reticular pattern at baseline. Geographic atrophy was seen in two eyes with focal AF pattern and one eye with focal-plaque-like pattern at baseline. A total of 11 eyes presented with severe visual loss (> or = 6 ETDRS lines). Ten (91%) of these had patchy AF pattern.

CONCLUSION

Imaging of fundus AF in patients with age-related maculopathy allows identification of different patterns of fundus AF. Our preliminary data suggest that a patchy pattern of AF indicates a relatively high risk of progression to age-related macular degeneration with visual loss.

Fundus autofluorescence in patients with age-related macular degeneration and high risk of visual loss

PURPOSE

To describe fundus autofluorescence (AF) patterns and their change over time in patients with age-related macular degeneration (AMD) and high risk of visual loss participating in the drusen laser study (DLS).

DESIGN

Randomized clinical trial.

METHODS

The study population consisted of 29 patients (35 eyes) participating in the DLS, which is a prospective, randomized, controlled clinical trial of prophylactic laser therapy in patients with AMD and high risk of neovascular complications. The intervention consisted of 16 eyes having prophylactic laser and 19 receiving no treatment. The main outcome measures were changes in the distribution of drusen and AF. Patients were reviewed for a median follow-up or 24 months (range 12-36 months).

RESULTS

At baseline, four patterns of fundus AF were recognized: focal increased AF (n = 18), reticular AF (n = 3), combined focal and reticular AF (n = 2), and homogeneous AF (n = 12). At last follow-up, fundus AF remained unchanged in 15 untreated (78%) and in seven treated (43%) eyes. In only one untreated eye, focal areas of increased AF returned to background levels and were no longer detectable at last follow-up, compared with six treated eyes. This difference was statistically significant (P =.03). Only large foveal soft drusen (drusenoid pigment epithelium detachments) consistently corresponded with focal changes in AF, whereas no obvious correspondence was found between small soft drusen located elsewhere and changes in AF.

CONCLUSION

The lack of obvious correspondence between the distribution of drusen and of AF found in this study appears to indicate that drusen and AF represent independent measures of aging in the posterior pole.

Polypoidal choroidal vasculopathy in exudative and haemorrhagic pigment epithelial detachments

AIMS

To determine the prevalence of polypoidal choroidopathy in consecutive patients presenting with large haemorrhagic and exudative neurosensory retinal and retinal pigment epithelial detachments (PEDs) of over 2 mm in diameter in the absence of drusen.

METHODS

40 patients were identified over a 5 month period of which 29 had haemorrhagic detachments, and 11 had purely exudative detachments. All had indocyanine green (ICG) angiography, and the presence was sought of large blood vessels in the choroid associated with localised dilated terminals that filled slowly and leaked ICG.

RESULTS

In 34 cases (85%) there was an appearance consistent with previous descriptions of idiopathic polypoidal choroidal vasculopathy. Of the six without polypoidal lesions the disorder was attributed to choroidal neovascularisation in four, chorioretinitis in one, and a fibrovascular PED in one. Of those with polypoidal lesions 20 (65%) were female, the mean age was 65.4 years (range 44-88), and 25 (74%) were white, seven (20%) black, and two (6%) east Asian. Eight had a history of hypertension. Visual acuity varied from 6/6 to counting fingers in the involved eye (mean 6/24). Bilateral polypoidal choroidal lesions were demonstrated in 16 patients (47%). The predominant location for these lesions was the macular region in 23 patients (68%). Polypoidal vasculopathy was found in 16 patients (47%) who had a previous diagnosis of age related macular disease (AMD). No patients had evidence of intraocular inflammation.

CONCLUSIONS

In a largely white patient population a high proportion of patients with haemorrhagic and exudative PEDs has evidence of polypoidal lesions on ICG angiography.

Structure of abnormal molecular assemblies (collagen VI) associated with human full thickness macular holes

Transversely banded deposits with an approximately 100-nm periodicity have been seen in association with a number of eye pathologies (e.g., age-related macular degeneration). Recently such aggregates have also been discovered in the cortical vitreous of a patient suffering from full thickness macular holes. The aggregates in the vitreous were of sufficient size and regularity for us to attempt 3D ultrastructural studies in the electron microscope. The molecules forming this aggregate pack in a centered tetragonal unit cell of dimensions approximately 26 x 26 x 180 nm. A real-space (r-weighted back projection) 3D reconstruction was computed. The aggregate is discussed in terms of its possible protein constituents. Collagen VI has been singled out as the most likely protein to form the aggregate. Two alternative models for the molecular packing are proposed, comprising aggregates of molecular tetramers or octamers. Understanding the structure of these abnormal banded deposits in the eye should help to throw light on the pathophysiological mechanisms of the diseases, including age-related macular degeneration, in which they occur.

Spatial extent of pigment epithelial detachments in age-related macular degeneration

OBJECTIVE

To quantify the spatial extent of pigment epithelial detachment (PED) associated with age-related macular degeneration (AMD) using a rapid, noninvasive method.

DESIGN

Prospective, cross-sectional study.

PARTICIPANTS

The authors tested 32 eyes of 21 patients (13 women and 8 men) with AMD 56 to 91 years of age (mean = 72.8 years). The authors retested seven eyes of six patients.

INTERVENTION

Three-dimensional imaging and quantification of PED were performed in each subject using confocal infrared imaging (790 nm) with a Topographic Scanning System (TopSS). The data consisted of a series of 32 images within a 3-mm-depth range requiring 0.9 second. Three-dimensional calculations were made from the series.

MAIN OUTCOME MEASURE

Height, diameter, area, volume, and slope of each PED were obtained with two calculation methods. The Ellipse Method used a graphics tool to draw elliptical borders circumscribing the region of interest in the image. The software automatically calculated the values for all parameters for the region inside the ellipse, with the retinal reference plane adjusted to match the height of the surrounding retina. The User-Defined Region Method differed in that the region of interest was drawn manually.

RESULTS

PEDs were easily detected in all patients using the TopSS. Maximum height of all PEDs above the reference plane ranged from 0.204 to 1.818 mm (mean = 0.57 mm). The diameter was 0.501 to 5.151 mm (mean = 2.711 mm), area was 0.179 to 20.402 mm2 (mean = 6.585 mm2), and volume was 0.012 to 13.981 mm3 (mean = 2.173 mm3). Intraobserver variability was low, with correlations between first and second measurements for the first visit ranging from r = 0.906 to 0.997 for slope and diameter, respectively.

CONCLUSIONS

Three-dimensional analysis with the TopSS provides objective outcome measures not obtainable with typical clinical methods such as fundus photography and angiography. Height and volume are crucial in determining whether neovascularization is worsening or persistent after photocoagulation. More longitudinal data are needed to determine whether tomographic data reduce the need for angiography. Unique to scanning laser tomography, exudative features were imaged at different depths.

Drusen in age-related macular degeneration: pathogenesis, natural course, and laser photocoagulation-induced regression

Drusen are subretinal pigment epithelial deposits that are characteristic of but not uniquely associated with age-related macular degeneration (AMD). Age-related macular degeneration is associated with two types of drusen that have different clinical appearances and different prognoses. Hard drusen appear as small, punctate, yellow nodules and can precede the development of atrophic AMD. Areolar atrophy of the retinal pigment epithelium (RPE), choriocapillaris, and outer retina develop as the drusen disappear, but drusen can regress without evidence of atrophy. Soft drusen appear as large (usually larger than 63 microm in diameter), pale yellow or grayish-white, dome-shaped elevations that can resemble localized serous RPE detachments. They tend to precede the development of clinically evident RPE detachments and choroidal neovascularization. Drusen characteristics correlated with progression to exudative maculopathy include drusen number (five or more), drusen size (larger than 63 microm in diameter), and confluence of drusen. Focal hyperpigmentation in the macula and systemic hypertension also are associated with an increased risk of developing choroidal new vessels (CNVs). Large drusen are usually a sign of diffuse thickening of Bruch's membrane with basal linear deposit, a vesicular material that probably arises from the RPE, constitutes a diffusion barrier to water-soluble constituents in the plasma, results in lipidization of Bruch's membrane, and creates a potential cleavage plane between the RPE basement membrane and the inner collagenous layer of Bruch's membrane through which CNVs can grow. Disappearance of drusen spontaneously and in areas adjacent to laser photocoagulation scars was first noted by Gass (Gass JD: Arch Ophthalmol 90:206-217, 1973; Trans Am Acad Ophthalmol Otolaryngol 75:580-608, 1971). Subsequent reports have confirmed these observations. Photocoagulation-induced drusen regression might prevent patients with drusen from developing exudative maculopathy. The mechanism for spontaneous drusen regression probably involves RPE atrophy. The mechanism for photocoagulation-induced drusen regression is unknown. If photocoagulation-induced drusen regression is anatomically similar to atrophy-associated drusen regression, then the former will be associated with dissolution of basal linear deposit and a residuum of basal laminar deposit. Sarks and coworkers (Sarks JP, Sarks SH, Killingsworth MC: Eye 11:515-522, 1997) proposed that this in turn will eliminate the potential cleavage plane between the RPE basement membrane and inner collagenous layer of Bruch's membrane through which CNVs grow, thus retarding the growth of CNVs.

Early drusen formation in the normal and aging eye and their relation to age related maculopathy: a clinicopathological study

AIM

To describe the early formation of drusen and their relation to normal aging changes at the macula and to the development of age related maculopathy (ARM).

METHOD

Histopathological features of 353 eyes without histological evidence of ARM are described and correlated with the clinical appearance. In addition, 45 of these eyes were examined by transmission electron microscopy.

RESULTS

Drusen were detected histopathologically in 177 (50%) eyes but were seen clinically in only 34% of these. Drusen were mainly small hard drusen with an occasional soft distinct drusen: no soft indistinct drusen were seen. Only those drusen deposits larger than 25-30 microns in diameter were detectable clinically. Preclinical drusen in eyes with only an occasional drusen were seen on electron microscopy as entrapment sites of coated membrane bound bodies which formed adjacent to the inner collagenous zone of Bruch's membrane. In contrast, preclinical drusen deposits in eyes with many drusen were seen as accumulations of amorphous material which appeared hyalinised by light microscopy. A distinct feature were rows of dense hyalinised microdrusen (1-2 microns in diameter), over which larger globular hyalinised drusen formed.

CONCLUSION

Histological and ultrastructural examination can recognise and distinguish the earliest drusen formed as a result of normal aging from those associated with ARM. In eyes without diffuse deposits, histologically all drusen were of the hard hyalinised variety or their derivatives; no soft drusen composed of membranous debris were found. These findings support and explain those of other authors who do not consider the presence of a few small hard drusen to be a risk factor for the development of ARM.